Concrete compositions contain hydraulically setting binders such as cement, fillers, such as sand or gravel and if necessary other additives. By addition of water, the concrete compositions are mixed and converted into fresh concrete, which can then be used by the known methods in construction engineering. Setting of the fresh concrete leads to solid concrete. Depending on the field of use, the solid concrete must possess a particular property profile. Thus for the production of rolling shafts in mining, industrial floors or for slope stabilization, tunnel lining and stabilization, especially high requirements are set for the abrasion resistance or the stability under impact stress of solid concrete. In order to fulfill such requirements, fiber-containing concrete is for example recommended in EP-A 32421. Suitable fibers are for example steel, glass or polyethylene fibers. Concrete reinforced with steel wire is described in DE-A 1941223.
However, through the use of fibers alone the stability of concrete required in many applications cannot be attained, even if the content of fibers is increased. For with increasing content of fibers the workability of the fresh concrete, such as its pumpability, decreases or there is an inhomogeneous distribution of the fibers in the fresh concrete, so-called “balling”, which adversely affects the properties of the solid concrete.
In DE-A 2856764, concrete mixtures based on hydraulically setting binders, additives such as polymers with low temperature tack, plastic fibers and molded plastic shapes are disclosed. As polymers, homopolymers are essentially used. The polymers of DE-A 2856764 have a low temperature tack with Tmax values of less than −8° C. (measured as per DIN 53445), which corresponds to a glass transition temperature Tg of <−15° C. (measured by dynamic differential calorimetry, DSC). To achieve these Tmax values, polymers of short chain length were used or plasticizers were added. Finally, such polymers as a component of concrete compositions lead to solid concrete which is still unsatisfactory as regards internal cohesion and strength. In addition, external plasticizers can easily become extracted from the concrete matrix in the course of time. Overall, owing to these fundamental features of DE-A 2856764, the property profile of corresponding solid concretes is limited, for example their resistance to abrasion or erosion, particularly with intensive long-term stress.
Against this background, the problem was to provide fiber-containing concrete compositions which finally lead to solid concrete which does not have the aforesaid disadvantages, in particular the solid concrete should also resist severe stresses such as abrasion or impact stress.